1 // SPDX-License-Identifier: GPL-2.0 2 /****************************************************************************/ 3 /* 4 * linux/fs/binfmt_flat.c 5 * 6 * Copyright (C) 2000-2003 David McCullough <davidm@snapgear.com> 7 * Copyright (C) 2002 Greg Ungerer <gerg@snapgear.com> 8 * Copyright (C) 2002 SnapGear, by Paul Dale <pauli@snapgear.com> 9 * Copyright (C) 2000, 2001 Lineo, by David McCullough <davidm@lineo.com> 10 * based heavily on: 11 * 12 * linux/fs/binfmt_aout.c: 13 * Copyright (C) 1991, 1992, 1996 Linus Torvalds 14 * linux/fs/binfmt_flat.c for 2.0 kernel 15 * Copyright (C) 1998 Kenneth Albanowski <kjahds@kjahds.com> 16 * JAN/99 -- coded full program relocation (gerg@snapgear.com) 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/kernel.h> 22 #include <linux/sched.h> 23 #include <linux/sched/task_stack.h> 24 #include <linux/mm.h> 25 #include <linux/mman.h> 26 #include <linux/errno.h> 27 #include <linux/signal.h> 28 #include <linux/string.h> 29 #include <linux/fs.h> 30 #include <linux/file.h> 31 #include <linux/ptrace.h> 32 #include <linux/user.h> 33 #include <linux/slab.h> 34 #include <linux/binfmts.h> 35 #include <linux/personality.h> 36 #include <linux/init.h> 37 #include <linux/flat.h> 38 #include <linux/uaccess.h> 39 #include <linux/vmalloc.h> 40 41 #include <asm/byteorder.h> 42 #include <linux/unaligned.h> 43 #include <asm/cacheflush.h> 44 #include <asm/page.h> 45 #include <asm/flat.h> 46 47 #ifndef flat_get_relocate_addr 48 #define flat_get_relocate_addr(rel) (rel) 49 #endif 50 51 /****************************************************************************/ 52 53 /* 54 * User data (data section and bss) needs to be aligned. 55 * We pick 0x20 here because it is the max value elf2flt has always 56 * used in producing FLAT files, and because it seems to be large 57 * enough to make all the gcc alignment related tests happy. 58 */ 59 #define FLAT_DATA_ALIGN (0x20) 60 61 /* 62 * User data (stack) also needs to be aligned. 63 * Here we can be a bit looser than the data sections since this 64 * needs to only meet arch ABI requirements. 65 */ 66 #define FLAT_STACK_ALIGN max_t(unsigned long, sizeof(void *), ARCH_SLAB_MINALIGN) 67 68 #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ 69 #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ 70 71 #define MAX_SHARED_LIBS (1) 72 73 #ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET 74 #define DATA_START_OFFSET_WORDS (0) 75 #define MAX_SHARED_LIBS_UPDATE (0) 76 #else 77 #define DATA_START_OFFSET_WORDS (MAX_SHARED_LIBS) 78 #define MAX_SHARED_LIBS_UPDATE (MAX_SHARED_LIBS) 79 #endif 80 81 struct lib_info { 82 struct { 83 unsigned long start_code; /* Start of text segment */ 84 unsigned long start_data; /* Start of data segment */ 85 unsigned long start_brk; /* End of data segment */ 86 unsigned long text_len; /* Length of text segment */ 87 unsigned long entry; /* Start address for this module */ 88 unsigned long build_date; /* When this one was compiled */ 89 bool loaded; /* Has this library been loaded? */ 90 } lib_list[MAX_SHARED_LIBS]; 91 }; 92 93 static int load_flat_binary(struct linux_binprm *); 94 95 static struct linux_binfmt flat_format = { 96 .module = THIS_MODULE, 97 .load_binary = load_flat_binary, 98 }; 99 100 101 /****************************************************************************/ 102 /* 103 * create_flat_tables() parses the env- and arg-strings in new user 104 * memory and creates the pointer tables from them, and puts their 105 * addresses on the "stack", recording the new stack pointer value. 106 */ 107 108 static int create_flat_tables(struct linux_binprm *bprm, unsigned long arg_start) 109 { 110 char __user *p; 111 unsigned long __user *sp; 112 long i, len; 113 114 p = (char __user *)arg_start; 115 sp = (unsigned long __user *)current->mm->start_stack; 116 117 sp -= bprm->envc + 1; 118 sp -= bprm->argc + 1; 119 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) 120 sp -= 2; /* argvp + envp */ 121 sp -= 1; /* &argc */ 122 123 current->mm->start_stack = (unsigned long)sp & -FLAT_STACK_ALIGN; 124 sp = (unsigned long __user *)current->mm->start_stack; 125 126 if (put_user(bprm->argc, sp++)) 127 return -EFAULT; 128 if (IS_ENABLED(CONFIG_BINFMT_FLAT_ARGVP_ENVP_ON_STACK)) { 129 unsigned long argv, envp; 130 argv = (unsigned long)(sp + 2); 131 envp = (unsigned long)(sp + 2 + bprm->argc + 1); 132 if (put_user(argv, sp++) || put_user(envp, sp++)) 133 return -EFAULT; 134 } 135 136 current->mm->arg_start = (unsigned long)p; 137 for (i = bprm->argc; i > 0; i--) { 138 if (put_user((unsigned long)p, sp++)) 139 return -EFAULT; 140 len = strnlen_user(p, MAX_ARG_STRLEN); 141 if (!len || len > MAX_ARG_STRLEN) 142 return -EINVAL; 143 p += len; 144 } 145 if (put_user(0, sp++)) 146 return -EFAULT; 147 current->mm->arg_end = (unsigned long)p; 148 149 current->mm->env_start = (unsigned long) p; 150 for (i = bprm->envc; i > 0; i--) { 151 if (put_user((unsigned long)p, sp++)) 152 return -EFAULT; 153 len = strnlen_user(p, MAX_ARG_STRLEN); 154 if (!len || len > MAX_ARG_STRLEN) 155 return -EINVAL; 156 p += len; 157 } 158 if (put_user(0, sp++)) 159 return -EFAULT; 160 current->mm->env_end = (unsigned long)p; 161 162 return 0; 163 } 164 165 /****************************************************************************/ 166 167 #ifdef CONFIG_BINFMT_ZFLAT 168 169 #include <linux/zlib.h> 170 171 #define LBUFSIZE 4000 172 173 /* gzip flag byte */ 174 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 175 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 176 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 177 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 178 #define COMMENT 0x10 /* bit 4 set: file comment present */ 179 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 180 #define RESERVED 0xC0 /* bit 6,7: reserved */ 181 182 static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst, 183 long len, int fd) 184 { 185 unsigned char *buf; 186 z_stream strm; 187 int ret, retval; 188 189 pr_debug("decompress_exec(offset=%llx,buf=%p,len=%lx)\n", fpos, dst, len); 190 191 memset(&strm, 0, sizeof(strm)); 192 strm.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL); 193 if (!strm.workspace) 194 return -ENOMEM; 195 196 buf = kmalloc(LBUFSIZE, GFP_KERNEL); 197 if (!buf) { 198 retval = -ENOMEM; 199 goto out_free; 200 } 201 202 /* Read in first chunk of data and parse gzip header. */ 203 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); 204 205 strm.next_in = buf; 206 strm.avail_in = ret; 207 strm.total_in = 0; 208 209 retval = -ENOEXEC; 210 211 /* Check minimum size -- gzip header */ 212 if (ret < 10) { 213 pr_debug("file too small?\n"); 214 goto out_free_buf; 215 } 216 217 /* Check gzip magic number */ 218 if ((buf[0] != 037) || ((buf[1] != 0213) && (buf[1] != 0236))) { 219 pr_debug("unknown compression magic?\n"); 220 goto out_free_buf; 221 } 222 223 /* Check gzip method */ 224 if (buf[2] != 8) { 225 pr_debug("unknown compression method?\n"); 226 goto out_free_buf; 227 } 228 /* Check gzip flags */ 229 if ((buf[3] & ENCRYPTED) || (buf[3] & CONTINUATION) || 230 (buf[3] & RESERVED)) { 231 pr_debug("unknown flags?\n"); 232 goto out_free_buf; 233 } 234 235 ret = 10; 236 if (buf[3] & EXTRA_FIELD) { 237 ret += 2 + buf[10] + (buf[11] << 8); 238 if (unlikely(ret >= LBUFSIZE)) { 239 pr_debug("buffer overflow (EXTRA)?\n"); 240 goto out_free_buf; 241 } 242 } 243 if (buf[3] & ORIG_NAME) { 244 while (ret < LBUFSIZE && buf[ret++] != 0) 245 ; 246 if (unlikely(ret == LBUFSIZE)) { 247 pr_debug("buffer overflow (ORIG_NAME)?\n"); 248 goto out_free_buf; 249 } 250 } 251 if (buf[3] & COMMENT) { 252 while (ret < LBUFSIZE && buf[ret++] != 0) 253 ; 254 if (unlikely(ret == LBUFSIZE)) { 255 pr_debug("buffer overflow (COMMENT)?\n"); 256 goto out_free_buf; 257 } 258 } 259 260 strm.next_in += ret; 261 strm.avail_in -= ret; 262 263 strm.next_out = dst; 264 strm.avail_out = len; 265 strm.total_out = 0; 266 267 if (zlib_inflateInit2(&strm, -MAX_WBITS) != Z_OK) { 268 pr_debug("zlib init failed?\n"); 269 goto out_free_buf; 270 } 271 272 while ((ret = zlib_inflate(&strm, Z_NO_FLUSH)) == Z_OK) { 273 ret = kernel_read(bprm->file, buf, LBUFSIZE, &fpos); 274 if (ret <= 0) 275 break; 276 len -= ret; 277 278 strm.next_in = buf; 279 strm.avail_in = ret; 280 strm.total_in = 0; 281 } 282 283 if (ret < 0) { 284 pr_debug("decompression failed (%d), %s\n", 285 ret, strm.msg); 286 goto out_zlib; 287 } 288 289 retval = 0; 290 out_zlib: 291 zlib_inflateEnd(&strm); 292 out_free_buf: 293 kfree(buf); 294 out_free: 295 kfree(strm.workspace); 296 return retval; 297 } 298 299 #endif /* CONFIG_BINFMT_ZFLAT */ 300 301 /****************************************************************************/ 302 303 static unsigned long 304 calc_reloc(unsigned long r, struct lib_info *p) 305 { 306 unsigned long addr; 307 unsigned long start_brk; 308 unsigned long start_data; 309 unsigned long text_len; 310 unsigned long start_code; 311 312 start_brk = p->lib_list[0].start_brk; 313 start_data = p->lib_list[0].start_data; 314 start_code = p->lib_list[0].start_code; 315 text_len = p->lib_list[0].text_len; 316 317 if (r > start_brk - start_data + text_len) { 318 pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", 319 r, start_brk-start_data+text_len, text_len); 320 goto failed; 321 } 322 323 if (r < text_len) /* In text segment */ 324 addr = r + start_code; 325 else /* In data segment */ 326 addr = r - text_len + start_data; 327 328 /* Range checked already above so doing the range tests is redundant...*/ 329 return addr; 330 331 failed: 332 pr_cont(", killing %s!\n", current->comm); 333 send_sig(SIGSEGV, current, 0); 334 335 return RELOC_FAILED; 336 } 337 338 /****************************************************************************/ 339 340 #ifdef CONFIG_BINFMT_FLAT_OLD 341 static void old_reloc(unsigned long rl) 342 { 343 static const char *segment[] = { "TEXT", "DATA", "BSS", "*UNKNOWN*" }; 344 flat_v2_reloc_t r; 345 unsigned long __user *ptr; 346 unsigned long val; 347 348 r.value = rl; 349 #if defined(CONFIG_COLDFIRE) 350 ptr = (unsigned long __user *)(current->mm->start_code + r.reloc.offset); 351 #else 352 ptr = (unsigned long __user *)(current->mm->start_data + r.reloc.offset); 353 #endif 354 get_user(val, ptr); 355 356 pr_debug("Relocation of variable at DATASEG+%x " 357 "(address %p, currently %lx) into segment %s\n", 358 r.reloc.offset, ptr, val, segment[r.reloc.type]); 359 360 switch (r.reloc.type) { 361 case OLD_FLAT_RELOC_TYPE_TEXT: 362 val += current->mm->start_code; 363 break; 364 case OLD_FLAT_RELOC_TYPE_DATA: 365 val += current->mm->start_data; 366 break; 367 case OLD_FLAT_RELOC_TYPE_BSS: 368 val += current->mm->end_data; 369 break; 370 default: 371 pr_err("Unknown relocation type=%x\n", r.reloc.type); 372 break; 373 } 374 put_user(val, ptr); 375 376 pr_debug("Relocation became %lx\n", val); 377 } 378 #endif /* CONFIG_BINFMT_FLAT_OLD */ 379 380 /****************************************************************************/ 381 382 static inline u32 __user *skip_got_header(u32 __user *rp) 383 { 384 if (IS_ENABLED(CONFIG_RISCV)) { 385 /* 386 * RISC-V has a 16 byte GOT PLT header for elf64-riscv 387 * and 8 byte GOT PLT header for elf32-riscv. 388 * Skip the whole GOT PLT header, since it is reserved 389 * for the dynamic linker (ld.so). 390 */ 391 u32 rp_val0, rp_val1; 392 393 if (get_user(rp_val0, rp)) 394 return rp; 395 if (get_user(rp_val1, rp + 1)) 396 return rp; 397 398 if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff) 399 rp += 4; 400 else if (rp_val0 == 0xffffffff) 401 rp += 2; 402 } 403 return rp; 404 } 405 406 static int load_flat_file(struct linux_binprm *bprm, 407 struct lib_info *libinfo, unsigned long *extra_stack) 408 { 409 struct flat_hdr *hdr; 410 unsigned long textpos, datapos, realdatastart; 411 u32 text_len, data_len, bss_len, stack_len, full_data, flags; 412 unsigned long len, memp, memp_size, extra, rlim; 413 __be32 __user *reloc; 414 u32 __user *rp; 415 int i, rev, relocs; 416 loff_t fpos; 417 unsigned long start_code, end_code; 418 ssize_t result; 419 int ret; 420 421 hdr = ((struct flat_hdr *) bprm->buf); /* exec-header */ 422 423 text_len = ntohl(hdr->data_start); 424 data_len = ntohl(hdr->data_end) - ntohl(hdr->data_start); 425 bss_len = ntohl(hdr->bss_end) - ntohl(hdr->data_end); 426 stack_len = ntohl(hdr->stack_size); 427 if (extra_stack) { 428 stack_len += *extra_stack; 429 *extra_stack = stack_len; 430 } 431 relocs = ntohl(hdr->reloc_count); 432 flags = ntohl(hdr->flags); 433 rev = ntohl(hdr->rev); 434 full_data = data_len + relocs * sizeof(unsigned long); 435 436 if (strncmp(hdr->magic, "bFLT", 4)) { 437 /* 438 * Previously, here was a printk to tell people 439 * "BINFMT_FLAT: bad header magic". 440 * But for the kernel which also use ELF FD-PIC format, this 441 * error message is confusing. 442 * because a lot of people do not manage to produce good 443 */ 444 ret = -ENOEXEC; 445 goto err; 446 } 447 448 if (flags & FLAT_FLAG_KTRACE) 449 pr_info("Loading file: %s\n", bprm->filename); 450 451 #ifdef CONFIG_BINFMT_FLAT_OLD 452 if (rev != FLAT_VERSION && rev != OLD_FLAT_VERSION) { 453 pr_err("bad flat file version 0x%x (supported 0x%lx and 0x%lx)\n", 454 rev, FLAT_VERSION, OLD_FLAT_VERSION); 455 ret = -ENOEXEC; 456 goto err; 457 } 458 459 /* 460 * fix up the flags for the older format, there were all kinds 461 * of endian hacks, this only works for the simple cases 462 */ 463 if (rev == OLD_FLAT_VERSION && 464 (flags || IS_ENABLED(CONFIG_BINFMT_FLAT_OLD_ALWAYS_RAM))) 465 flags = FLAT_FLAG_RAM; 466 467 #else /* CONFIG_BINFMT_FLAT_OLD */ 468 if (rev != FLAT_VERSION) { 469 pr_err("bad flat file version 0x%x (supported 0x%lx)\n", 470 rev, FLAT_VERSION); 471 ret = -ENOEXEC; 472 goto err; 473 } 474 #endif /* !CONFIG_BINFMT_FLAT_OLD */ 475 476 /* 477 * Make sure the header params are sane. 478 * 28 bits (256 MB) is way more than reasonable in this case. 479 * If some top bits are set we have probable binary corruption. 480 */ 481 if ((text_len | data_len | bss_len | stack_len | full_data) >> 28) { 482 pr_err("bad header\n"); 483 ret = -ENOEXEC; 484 goto err; 485 } 486 487 #ifndef CONFIG_BINFMT_ZFLAT 488 if (flags & (FLAT_FLAG_GZIP|FLAT_FLAG_GZDATA)) { 489 pr_err("Support for ZFLAT executables is not enabled.\n"); 490 ret = -ENOEXEC; 491 goto err; 492 } 493 #endif 494 495 /* 496 * Check initial limits. This avoids letting people circumvent 497 * size limits imposed on them by creating programs with large 498 * arrays in the data or bss. 499 */ 500 rlim = rlimit(RLIMIT_DATA); 501 if (rlim >= RLIM_INFINITY) 502 rlim = ~0; 503 if (data_len + bss_len > rlim) { 504 ret = -ENOMEM; 505 goto err; 506 } 507 508 /* Flush all traces of the currently running executable */ 509 ret = begin_new_exec(bprm); 510 if (ret) 511 goto err; 512 513 /* OK, This is the point of no return */ 514 set_personality(PER_LINUX_32BIT); 515 setup_new_exec(bprm); 516 517 /* 518 * calculate the extra space we need to map in 519 */ 520 extra = max_t(unsigned long, bss_len + stack_len, 521 relocs * sizeof(unsigned long)); 522 523 /* 524 * there are a couple of cases here, the separate code/data 525 * case, and then the fully copied to RAM case which lumps 526 * it all together. 527 */ 528 if (!IS_ENABLED(CONFIG_MMU) && !(flags & (FLAT_FLAG_RAM|FLAT_FLAG_GZIP))) { 529 /* 530 * this should give us a ROM ptr, but if it doesn't we don't 531 * really care 532 */ 533 pr_debug("ROM mapping of file (we hope)\n"); 534 535 textpos = vm_mmap(bprm->file, 0, text_len, PROT_READ|PROT_EXEC, 536 MAP_PRIVATE, 0); 537 if (!textpos || IS_ERR_VALUE(textpos)) { 538 ret = textpos; 539 if (!textpos) 540 ret = -ENOMEM; 541 pr_err("Unable to mmap process text, errno %d\n", ret); 542 goto err; 543 } 544 545 len = data_len + extra + 546 DATA_START_OFFSET_WORDS * sizeof(unsigned long); 547 len = PAGE_ALIGN(len); 548 realdatastart = vm_mmap(NULL, 0, len, 549 PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE, 0); 550 551 if (realdatastart == 0 || IS_ERR_VALUE(realdatastart)) { 552 ret = realdatastart; 553 if (!realdatastart) 554 ret = -ENOMEM; 555 pr_err("Unable to allocate RAM for process data, " 556 "errno %d\n", ret); 557 vm_munmap(textpos, text_len); 558 goto err; 559 } 560 datapos = ALIGN(realdatastart + 561 DATA_START_OFFSET_WORDS * sizeof(unsigned long), 562 FLAT_DATA_ALIGN); 563 564 pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", 565 data_len + bss_len + stack_len, datapos); 566 567 fpos = ntohl(hdr->data_start); 568 #ifdef CONFIG_BINFMT_ZFLAT 569 if (flags & FLAT_FLAG_GZDATA) { 570 result = decompress_exec(bprm, fpos, (char *)datapos, 571 full_data, 0); 572 } else 573 #endif 574 { 575 result = read_code(bprm->file, datapos, fpos, 576 full_data); 577 } 578 if (IS_ERR_VALUE(result)) { 579 ret = result; 580 pr_err("Unable to read data+bss, errno %d\n", ret); 581 vm_munmap(textpos, text_len); 582 vm_munmap(realdatastart, len); 583 goto err; 584 } 585 586 reloc = (__be32 __user *) 587 (datapos + (ntohl(hdr->reloc_start) - text_len)); 588 memp = realdatastart; 589 memp_size = len; 590 } else { 591 592 len = text_len + data_len + extra + 593 DATA_START_OFFSET_WORDS * sizeof(u32); 594 len = PAGE_ALIGN(len); 595 textpos = vm_mmap(NULL, 0, len, 596 PROT_READ | PROT_EXEC | PROT_WRITE, MAP_PRIVATE, 0); 597 598 if (!textpos || IS_ERR_VALUE(textpos)) { 599 ret = textpos; 600 if (!textpos) 601 ret = -ENOMEM; 602 pr_err("Unable to allocate RAM for process text/data, " 603 "errno %d\n", ret); 604 goto err; 605 } 606 607 realdatastart = textpos + ntohl(hdr->data_start); 608 datapos = ALIGN(realdatastart + 609 DATA_START_OFFSET_WORDS * sizeof(u32), 610 FLAT_DATA_ALIGN); 611 612 reloc = (__be32 __user *) 613 (datapos + (ntohl(hdr->reloc_start) - text_len)); 614 memp = textpos; 615 memp_size = len; 616 #ifdef CONFIG_BINFMT_ZFLAT 617 /* 618 * load it all in and treat it like a RAM load from now on 619 */ 620 if (flags & FLAT_FLAG_GZIP) { 621 #ifndef CONFIG_MMU 622 result = decompress_exec(bprm, sizeof(struct flat_hdr), 623 (((char *)textpos) + sizeof(struct flat_hdr)), 624 (text_len + full_data 625 - sizeof(struct flat_hdr)), 626 0); 627 memmove((void *) datapos, (void *) realdatastart, 628 full_data); 629 #else 630 /* 631 * This is used on MMU systems mainly for testing. 632 * Let's use a kernel buffer to simplify things. 633 */ 634 long unz_text_len = text_len - sizeof(struct flat_hdr); 635 long unz_len = unz_text_len + full_data; 636 char *unz_data = vmalloc(unz_len); 637 if (!unz_data) { 638 result = -ENOMEM; 639 } else { 640 result = decompress_exec(bprm, sizeof(struct flat_hdr), 641 unz_data, unz_len, 0); 642 if (result == 0 && 643 (copy_to_user((void __user *)textpos + sizeof(struct flat_hdr), 644 unz_data, unz_text_len) || 645 copy_to_user((void __user *)datapos, 646 unz_data + unz_text_len, full_data))) 647 result = -EFAULT; 648 vfree(unz_data); 649 } 650 #endif 651 } else if (flags & FLAT_FLAG_GZDATA) { 652 result = read_code(bprm->file, textpos, 0, text_len); 653 if (!IS_ERR_VALUE(result)) { 654 #ifndef CONFIG_MMU 655 result = decompress_exec(bprm, text_len, (char *) datapos, 656 full_data, 0); 657 #else 658 char *unz_data = vmalloc(full_data); 659 if (!unz_data) { 660 result = -ENOMEM; 661 } else { 662 result = decompress_exec(bprm, text_len, 663 unz_data, full_data, 0); 664 if (result == 0 && 665 copy_to_user((void __user *)datapos, 666 unz_data, full_data)) 667 result = -EFAULT; 668 vfree(unz_data); 669 } 670 #endif 671 } 672 } else 673 #endif /* CONFIG_BINFMT_ZFLAT */ 674 { 675 result = read_code(bprm->file, textpos, 0, text_len); 676 if (!IS_ERR_VALUE(result)) 677 result = read_code(bprm->file, datapos, 678 ntohl(hdr->data_start), 679 full_data); 680 } 681 if (IS_ERR_VALUE(result)) { 682 ret = result; 683 pr_err("Unable to read code+data+bss, errno %d\n", ret); 684 vm_munmap(textpos, text_len + data_len + extra + 685 DATA_START_OFFSET_WORDS * sizeof(u32)); 686 goto err; 687 } 688 } 689 690 start_code = textpos + sizeof(struct flat_hdr); 691 end_code = textpos + text_len; 692 text_len -= sizeof(struct flat_hdr); /* the real code len */ 693 694 /* The main program needs a little extra setup in the task structure */ 695 current->mm->start_code = start_code; 696 current->mm->end_code = end_code; 697 current->mm->start_data = datapos; 698 current->mm->end_data = datapos + data_len; 699 /* 700 * set up the brk stuff, uses any slack left in data/bss/stack 701 * allocation. We put the brk after the bss (between the bss 702 * and stack) like other platforms. 703 * Userspace code relies on the stack pointer starting out at 704 * an address right at the end of a page. 705 */ 706 current->mm->start_brk = datapos + data_len + bss_len; 707 current->mm->brk = (current->mm->start_brk + 3) & ~3; 708 #ifndef CONFIG_MMU 709 current->mm->context.end_brk = memp + memp_size - stack_len; 710 #endif 711 712 if (flags & FLAT_FLAG_KTRACE) { 713 pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", 714 textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); 715 pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", 716 "Load", bprm->filename, 717 start_code, end_code, datapos, datapos + data_len, 718 datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); 719 } 720 721 /* Store the current module values into the global library structure */ 722 libinfo->lib_list[0].start_code = start_code; 723 libinfo->lib_list[0].start_data = datapos; 724 libinfo->lib_list[0].start_brk = datapos + data_len + bss_len; 725 libinfo->lib_list[0].text_len = text_len; 726 libinfo->lib_list[0].loaded = 1; 727 libinfo->lib_list[0].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; 728 libinfo->lib_list[0].build_date = ntohl(hdr->build_date); 729 730 /* 731 * We just load the allocations into some temporary memory to 732 * help simplify all this mumbo jumbo 733 * 734 * We've got two different sections of relocation entries. 735 * The first is the GOT which resides at the beginning of the data segment 736 * and is terminated with a -1. This one can be relocated in place. 737 * The second is the extra relocation entries tacked after the image's 738 * data segment. These require a little more processing as the entry is 739 * really an offset into the image which contains an offset into the 740 * image. 741 */ 742 if (flags & FLAT_FLAG_GOTPIC) { 743 rp = skip_got_header((u32 __user *) datapos); 744 for (; ; rp++) { 745 u32 addr, rp_val; 746 if (get_user(rp_val, rp)) 747 return -EFAULT; 748 if (rp_val == 0xffffffff) 749 break; 750 if (rp_val) { 751 addr = calc_reloc(rp_val, libinfo); 752 if (addr == RELOC_FAILED) { 753 ret = -ENOEXEC; 754 goto err; 755 } 756 if (put_user(addr, rp)) 757 return -EFAULT; 758 } 759 } 760 } 761 762 /* 763 * Now run through the relocation entries. 764 * We've got to be careful here as C++ produces relocatable zero 765 * entries in the constructor and destructor tables which are then 766 * tested for being not zero (which will always occur unless we're 767 * based from address zero). This causes an endless loop as __start 768 * is at zero. The solution used is to not relocate zero addresses. 769 * This has the negative side effect of not allowing a global data 770 * reference to be statically initialised to _stext (I've moved 771 * __start to address 4 so that is okay). 772 */ 773 if (rev > OLD_FLAT_VERSION) { 774 for (i = 0; i < relocs; i++) { 775 u32 addr, relval; 776 __be32 tmp; 777 778 /* 779 * Get the address of the pointer to be 780 * relocated (of course, the address has to be 781 * relocated first). 782 */ 783 if (get_user(tmp, reloc + i)) 784 return -EFAULT; 785 relval = ntohl(tmp); 786 addr = flat_get_relocate_addr(relval); 787 rp = (u32 __user *)calc_reloc(addr, libinfo); 788 if (rp == (u32 __user *)RELOC_FAILED) { 789 ret = -ENOEXEC; 790 goto err; 791 } 792 793 /* Get the pointer's value. */ 794 ret = flat_get_addr_from_rp(rp, relval, flags, &addr); 795 if (unlikely(ret)) 796 goto err; 797 798 if (addr != 0) { 799 /* 800 * Do the relocation. PIC relocs in the data section are 801 * already in target order 802 */ 803 if ((flags & FLAT_FLAG_GOTPIC) == 0) { 804 /* 805 * Meh, the same value can have a different 806 * byte order based on a flag.. 807 */ 808 addr = ntohl((__force __be32)addr); 809 } 810 addr = calc_reloc(addr, libinfo); 811 if (addr == RELOC_FAILED) { 812 ret = -ENOEXEC; 813 goto err; 814 } 815 816 /* Write back the relocated pointer. */ 817 ret = flat_put_addr_at_rp(rp, addr, relval); 818 if (unlikely(ret)) 819 goto err; 820 } 821 } 822 #ifdef CONFIG_BINFMT_FLAT_OLD 823 } else { 824 for (i = 0; i < relocs; i++) { 825 __be32 relval; 826 if (get_user(relval, reloc + i)) 827 return -EFAULT; 828 old_reloc(ntohl(relval)); 829 } 830 #endif /* CONFIG_BINFMT_FLAT_OLD */ 831 } 832 833 flush_icache_user_range(start_code, end_code); 834 835 /* zero the BSS, BRK and stack areas */ 836 if (clear_user((void __user *)(datapos + data_len), bss_len + 837 (memp + memp_size - stack_len - /* end brk */ 838 libinfo->lib_list[0].start_brk) + /* start brk */ 839 stack_len)) 840 return -EFAULT; 841 842 return 0; 843 err: 844 return ret; 845 } 846 847 848 /****************************************************************************/ 849 850 /* 851 * These are the functions used to load flat style executables and shared 852 * libraries. There is no binary dependent code anywhere else. 853 */ 854 855 static int load_flat_binary(struct linux_binprm *bprm) 856 { 857 struct lib_info libinfo; 858 struct pt_regs *regs = current_pt_regs(); 859 unsigned long stack_len = 0; 860 unsigned long start_addr; 861 int res; 862 int i, j; 863 864 memset(&libinfo, 0, sizeof(libinfo)); 865 866 /* 867 * We have to add the size of our arguments to our stack size 868 * otherwise it's too easy for users to create stack overflows 869 * by passing in a huge argument list. And yes, we have to be 870 * pedantic and include space for the argv/envp array as it may have 871 * a lot of entries. 872 */ 873 #ifndef CONFIG_MMU 874 stack_len += PAGE_SIZE * MAX_ARG_PAGES - bprm->p; /* the strings */ 875 #endif 876 stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */ 877 stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ 878 stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); 879 880 res = load_flat_file(bprm, &libinfo, &stack_len); 881 if (res < 0) 882 return res; 883 884 /* Update data segment pointers for all libraries */ 885 for (i = 0; i < MAX_SHARED_LIBS_UPDATE; i++) { 886 if (!libinfo.lib_list[i].loaded) 887 continue; 888 for (j = 0; j < MAX_SHARED_LIBS; j++) { 889 unsigned long val = libinfo.lib_list[j].loaded ? 890 libinfo.lib_list[j].start_data : UNLOADED_LIB; 891 unsigned long __user *p = (unsigned long __user *) 892 libinfo.lib_list[i].start_data; 893 p -= j + 1; 894 if (put_user(val, p)) 895 return -EFAULT; 896 } 897 } 898 899 set_binfmt(&flat_format); 900 901 #ifdef CONFIG_MMU 902 res = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); 903 if (!res) 904 res = create_flat_tables(bprm, bprm->p); 905 #else 906 /* Stash our initial stack pointer into the mm structure */ 907 current->mm->start_stack = 908 ((current->mm->context.end_brk + stack_len + 3) & ~3) - 4; 909 pr_debug("sp=%lx\n", current->mm->start_stack); 910 911 /* copy the arg pages onto the stack */ 912 res = transfer_args_to_stack(bprm, ¤t->mm->start_stack); 913 if (!res) 914 res = create_flat_tables(bprm, current->mm->start_stack); 915 #endif 916 if (res) 917 return res; 918 919 /* Fake some return addresses to ensure the call chain will 920 * initialise library in order for us. We are required to call 921 * lib 1 first, then 2, ... and finally the main program (id 0). 922 */ 923 start_addr = libinfo.lib_list[0].entry; 924 925 #ifdef FLAT_PLAT_INIT 926 FLAT_PLAT_INIT(regs); 927 #endif 928 929 finalize_exec(bprm); 930 pr_debug("start_thread(regs=0x%p, entry=0x%lx, start_stack=0x%lx)\n", 931 regs, start_addr, current->mm->start_stack); 932 start_thread(regs, start_addr, current->mm->start_stack); 933 934 return 0; 935 } 936 937 /****************************************************************************/ 938 939 static int __init init_flat_binfmt(void) 940 { 941 register_binfmt(&flat_format); 942 return 0; 943 } 944 core_initcall(init_flat_binfmt); 945 946 /****************************************************************************/ 947